Year	Percent
1998-01-01	5.74692274804767
1999-01-01	6.24331183494364
2000-01-01	5.91386723705048
2001-01-01	5.47247150733753
2002-01-01	5.38157791654401
2003-01-01	5.27023169942656
2004-01-01	5.86176052147775
2005-01-01	5.57329572808230
2006-01-01	5.01159021524344
2007-01-01	4.69538126377618
2008-01-01	4.19662809636851
2009-01-01	4.96224612082769
2010-01-01	6.18437741227937
2011-01-01	8.09004954788963
2012-01-01	10.66086612079720
2013-01-01	11.79107828595940